Orchids have been regarded as the symbol of elegance and refinement since ancient times and have received many praises from ancient poets and writers. With a history of cultivation in our country of a thousand years, there are still many people breeding them today. However, when breeding orchids, various diseases often occur. Let’s understand the symptoms and preventive measures of orchid anthracnose below:

Orchid anthracnose disease pictures Symptoms of orchid anthracnose

The symptoms of orchid anthracnose are very complex, and large ones can be divided into three types: circular black spots, annular soft spots, and withered leaves; when attacking the main stem of orchids, depending on the size of the seedlings, they are mainly divided into two categories: one infects the leaves of seedlings, often starting with deep brown small circles at the base of the leaves, expanding into annular spots, and in severe cases, the heart leaves rot: the other infects the leaves of older seedlings, with annular or elliptical spots on the leaves, and when the disease occurs at the edge of the leaves, it produces semicircular spots in the early stage: The spots of this disease are light brown soft spots in the early stage of the disease, turning into dark brown to grayish in the middle and late stages, with dark brown edges and a greenish halo around the edges, the diameter of the spots is mostly 0.1-0.5 cm, and in severe cases, the spots connect to form a strip-like soft spot. If the pest and disease cannot be controlled reasonably, the leaves will wither from top to bottom slowly; in the middle and late stages of the disease, the disease part produces black dot-shaped conidiophores, and when the relative humidity is high, it produces annular black dot pale pink collagenous substances, which are the source of spread of the pathogen – conidiophores.

Characteristics of anthracnose disease occurrence in orchids

1. The occurrence of this disease is related to the planting and management methods. This disease can occur throughout the year in Dali City, with the spring and autumn seasons having more severe disease occurrence, and the summer having lighter disease occurrence, which is mainly related to planting and management methods. In Dali City, summer (June to August) is the rainy season, with high humidity in the air. If water is continuously sprinkled on the orchid leaves in the orchid garden, the disease occurrence in summer may increase. Conversely, under natural humidity standards, if ventilation is improved and water sprinkling is reduced, the occurrence of the disease is not very severe. In addition, according to research, the disease occurs more severely in gardens with improper planting and management methods, such as finer potting soil, soil degradation, excessive watering, poor roots and stems, excessive application of base fertilizer, and poor ventilation standards.

2. The disease occurrence is related to the change of planting site. Seedlings cultivated in greenhouses without seedling hardening treatment are sold directly to living room gardeners with humidity control standards, which is prone to leaf dehydration and withering, as well as anthracnose disease of orchids, with typical symptoms of the orchid leaves withering from top to bottom gradually.

3. The disease occurrence is related to the strength of the orchid plant. In general, orchid plants with strong growth, good roots and stems, and rich and balanced nutrition are not prone to diseases. Poor seedlings, due to weak disease resistance, are more prone to getting sick. Conversely, seedlings with poor roots and stems and poor growth are more prone to getting sick due to weak disease resistance.

4. The disease occurrence is related to the length of breeding and training time. In Dali City, the planting of orchids is mainly dominated by Lianbanlan. The natural Lianbanlan cultivated at home has a high seedling rate, strong growth, and strong disease resistance in the first two years, but after many years of cultivation, the wildness declines, the disease resistance weakens, and the disease occurrence tends to increase. The most typical example is the Dianlan famous variety Xiaoxue, which has been cultivated at home for hundreds of years and is prone to anthracnose disease of orchids.

5. The disease resistance is strong in general for the types of orchids with thick and hard leaves, and those with leaves that stand upright, such as Phalaenopsis orchids, and the Iron Bone of Chunlan in the spring orchids, which have relatively light disease occurrence; however, the types such as Lianbanlan, Duoxiang and Lülan in Dali City, which are key for planting, are more susceptible to diseases: The famous Lianbanlan shops, due to excessive seedlings, have poor growth and are more prone to this disease.